In recent years, advances in technology, as well as ever evolving tastes in style, have led to substantial changes in the design of automobiles. One of the changes involves the complexity, as well as the power usage, of the various electrical systems within automobiles, particularly alternative fuel vehicles, such as hybrid, electric, and fuel cell vehicles.
The power and/or torque density required for motors used in such vehicles is extremely high. The amount of power or torque that can be generated by a particular motor is limited in large part by the winding, or coil, temperature within the motor during operation. If the motor is permitted to operate such that the winding temperature becomes too high, sensitive electrical components, such as semiconductor devices of the PIM, may be damaged.
One commonly used method of limiting PIM temperature is to calculate I2T (current to temperature) of output or DC current and to limit the duration of the peak current, which is fixed proportional to the nominal current of the specification. However, this approach does not consider the heating mechanism inside the PIM, and works in a completely open-loop manner.
Accordingly, it is desirable to provide a system and method for limiting the operating temperature of an electric motor that allows the operational temperature to be continuously controlled at various stages of operation. In addition, it is desirable to provide a system and method that facilitates continuous operation of the motor while limiting the operating temperature. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background.